Always listening for the enemy: Heinz Hoenig as Maat the sonar operator in the 1981 war epic Das Boot.

"It is on official record that a certain ship belonging to one of our great allies chased a sperm whale for - I forget how many miles. The chase was by hydrophone, aural, and did not become visual until many miles had been run, when the hydrophone experts were reluctantly compelled to admit that their legs had been pulled, or at any rate their ears tweaked. They state the fact that the sperm whale faithfully reproduced the sound of a U-boat running on electric motors throughout the entire chase." [Hush; or The Hydrophone Service, 1920 by H.W. Wilson]